The ability to rapidly, precisely and safely dispense viscous industrial materials, such as hot melt adhesives, is a modern-day necessity for many manufacturers. Accordingly, substantial resources have been invested for the purpose of improving the accuracy and performance of the processes responsible for the application of adhesives, caulks and sealants, for example. Resultant innovations such as electrically activated dispensing guns have greatly enhanced the ability of manufacturers to control fluid placement and flow rates, and have allowed for the accomplishment of more complex and sophisticated liquid dispensing patterns to be applied to a substrate. The challenges associated with meeting expanding industry requirements necessitate still greater improvements in the operational performance of electric gun dispensers.
Electric liquid dispensing guns generally include an electromagnetic coil surrounding an armature that is energized to produce an electromagnetic field with respect to a magnetic pole. The electromagnetic field is selectively controlled to open and close a dispensing valve by moving a valve stem connected to the armature. More specifically, the forces of magnetic attraction between the armature and the magnetic pole move the armature toward the pole, thereby opening the dispensing valve. At the end of a dispensing cycle, the electromagnetic coil is de-energized, and a return spring returns the armature and valve stem to their original positions, thereby closing the dispensing valve.
Driver circuits have been employed to regulate and control the current delivered to the electromagnetic coil. Thus, liquid is dispensed from the valve according to the magnitude of current supplied by the driver circuit. Supplied current levels correspond to the amount of current required to move the armature into an open position at the beginning of a dispensing cycle, as well as to the amount required to hold it in a position that allows continuous fluid application. Finally, an absence of current from the gun driver circuit effects a demagnetization of the coil and causes the dispensing valve to close.
The optimal operation of a liquid dispensing gun depends upon effective management of a number of factors, such as the electrical capabilities of the dispensing gun and the operating conditions for a particular liquid dispensing application. Several variables that must be taken into account include the viscosity and temperature of the liquid being dispensed, the configuration and number of dispensing guns, the pattern to be dispensed onto the substrate, the traveling speed of the substrate relative to the dispensing gun, and the frequency of the liquid dispensing cycles.
Proper accounting and management of the above operating conditions for a particular liquid dispensing application currently requires an operator to possess a sophisticated understanding of the electrical capabilities of the electric dispensing gun, and often necessitates cumbersome, expensive testing equipment to ensure that the proper dispensing parameters have been set. The requisite operator expertise is in part attributable to the absence of a generally understood and accessible interface to the electric dispensing gun that permits operating parameters of the gun to be set. For instance, settings on typical electric dispensing guns may be defined in terms of electrical quantities that relate to current values to be applied to the gun, such as peak current levels, duration of peak current and hold current level. Such terminology may not intuitively correlate with the operating conditions facing an operator, such as fluid viscosity, liquid dispensing pattern to be applied, line speed and equipment operating temperatures. Thus, an operator must convert and associate the operating conditions pertinent to a particular dispensing application with the optimum electrical settings of the gun controls. This conversion procedure may be prone to translational and mathematical errors, and may also result in the less than optimal utilization of liquid dispensing equipment.
The procedure for setting dispensing parameters is further complicated where a user must manually adjust the circuitry and settings of an electric dispensing gun. Controls responsible for setting dispensing parameters are commonly not designed for field modification and may be generally inaccessible. For instance, an operator may be required to mechanically adjust current settings by constantly manipulating a series of small dip switches or buttons, or by depressing arrows on a converted keypad. Consequently, manual adjustments are prone to error, and inconvenient placement of settings controls on the dispensing equipment may require operation of a gun to be halted in order for the controls to be accessed. Thus, the present manual adjustment of dispensing parameters of electric liquid dispensing guns has several known drawbacks.
Therefore, there is a need for an improved manner of guiding an operator toward a proper setup of an electric liquid dispensing gun and enabling convenient adjustment once the proper set-up has been determined.